A very knowledgeable reply! No site starts out with PR 10. You have to work from the ground and climb up gradually. But for the directories that remain PR O over the years, well, I think their administrators are not doing enough SEO, and I do not submit to such sites. Just a personal opinion, anyway.
Try the ways to improve your link popularity and keyword rankings which will bring traffic. PR is just importance of your site given by google which calculates your PR with the no. of quality backlinks your site has.